Absorbent articles are well known in the art. These articles typically have an absorbent core held or positioned in proximity to the body of a wearer during use by a fastening system in order to capture and absorb bodily exudates discharged from the wearer. Typical absorbent articles include a topsheet facing the wearer, which permits fluid exudates to pass through, and a backsheet, which prevents the exudates from escaping from the absorbent article.
Disposable absorbent articles such as diapers are designed to absorb and contain bodily waste in order to prevent soiling of the body and clothing of the wearer. The disposable diapers typically comprise a single design available in different sizes to fit a variety of wearers ranging from newborns to toddlers undergoing toilet training. The design of the diaper typically affects performance, such as, ability to absorb and contain bodily waste. The size of the diaper typically affects fit, for example, the size of the diaper waist opening, the size of the openings around the thighs, and the length or “pitch” of the diaper.
The toilet training stage may be referred to as the “point of exit” as toddlers typically leave the product category once training is successfully completed. The age at which children are toilet trained in “developed” countries has increased steadily over the past several decades and is now in the range of about 24-42 months. One reason toilet training has become delayed is due to significant technical improvements in diaper dryness and comfort. In modern diapers, the child has dry skin even after one or more urinations. As a result, the child feels little or no discomfort and often may not even be aware that they have urinated.
Many parents have the child wear cotton training pants or underwear during toilet training so the child feels discomfort following urination in their “pants”. It is believed that such discomfort assists with learning or provides motivation to learn proper toilet training. Cotton training pants leave the skin wet and, due to their high breathability, promote evaporative cooling of the skin, further enhancing discomfort. The current tradeoff in this approach, however, is that cotton training pants have poor urine containment leading to wet clothing and often times, wet surroundings e.g. carpeting, furniture, etc. Clearly there is a need to provide a training signal to the toilet training child while preventing urine leakage and unnecessary changes of clothing.
A number of attempts to address this need have been made in the art. One attempt (U.S. Pat. No. 5,681,298) involves the use of a liquid permeable temperature change member to provide a thermal signal to the child. The temperature change member comprises salts having positive (exothermic) or negative (endothermic) heats of solution in water and is disposed with the absorbent assembly. A key requirement is that the total energy change per unit area be about 6 to about 30 cal/cm2. This approach has several critical limitations. First, the liquid permeability of the temperature change member allows the salt to be dissolved and washed into the absorbent assembly, away from the skin of the wearer, significantly reducing the opportunity to provide a thermal signal to the skin. Additionally, the attempt to overcome this phenomenon via the requirement of the 6-30 cal/cm2 total energy change involves the use of significant quantities of the salt, increasing the cost and complexity of the product.
Thus, it would be desirable to provide a wearable article that can facilitate toilet training by providing an effective signal notifying the wearer by causing discomfort when a discharge of bodily waste has occurred while at the same time providing the protection of an absorbent article, preventing soiling of the wearer's clothing and surroundings. Particularly, it would be desirable to provide such a wearable article providing an effective thermal signal of urination using minimal amounts of endothermic or exothermic salt. Further it would be desirable to provide a thermal signal of urination with less than about 3 cal/cm2 total energy change.